In the previous 4 lectures I have been talking about thyroid when it functions normally, as designed. We have learned that thyroid gland makes hormones T3 and T4, that these hormones regulate the metabolism and energy production in all the cells of the body. This energy is essential for the cells to work, to develop, to multiply, to repair, in short do all the functions that the cells are supposed to do. And ideally, thyroid gland should produce more hormones than is actually required and store them, releasing into the blood just as many as the body needs, not more, not less.
That’s why normally thyroid is tightly regulated by the brain, which produces TRH (thytrophin releasing hormone) and TSH or thyroid stimulating hormone plus the negative feedback mechanism.
We learned that once made, the bulk of thyroid hormones is stored inside the thyroid gland. A small portion of the hormones is released into the blood where most are attached to special proteins, but some hormones are “free”, not attached to anything. These are hormones that do the work.
All this elaborate mechanism exists to make sure that every cell of the body has just as much thyroid hormone as it needs. That’s why the body makes sure that there are plenty of hormones in the thyroid gland, in the blood, bound to proteins, and in the blood not bound to anything, so called “free” hormones. This is what happens normally.
In the previous lecture I asked the question - why do we have 2 thyroid hormones? The answer is T4 is not really a hormone, it’s a precursor from which the real hormone is made. The real hormone that does the work is the free T3.
We talked about the composition of T3 and T4. Both have 2 amino acids tyrosines joined together. Tyrosine’s main feature is that it has a circular, or rather hexagonal, structure in the center to which either one or two atoms of iodine are attaches. T4 has 4 iodines, T3 has 3. To make T3 from T4, all you need to do is remove one of the iodines. Sounds simple, but it’s a bit more complicated than that.
First, to make T3 from T4, you need to remove one iodine from a specific location. In other words, not just any iodine, but one specific iodine out of the 4.
Imagine T4 as a can of food, say a can of beans. A can of beans is a good thing, it has food inside. But if all you have is a can, you will still go hungry because you can’t use it as is. You need a can opener to remove the top lid. Only then you’ll be able to get the food.
And it must be the top lid, because what happens if you remove the lower lid? Then whatever is in the can will fall out and get wasted, and you’ll still go hungry.
It’s the same with T4. If you remove the right iodine, you will have T3, the active thyroid hormone. If you remove the wrong iodine, you end up with something called reverse T3, which is completely inactive.
The removal of iodine from T4 is done by an enzyme called de-iodinase. There are several types of deiodinases, each removing an iodine from a particular position. They all require selenium to work properly. People deficient in selenium cannot make enough free T3, which can lead to low thyroid.
Some people ask why should we be making inactive reverse T3 at all? There are many reasons, the first one is that it is like an escape valve. It helps regulate how much free T3 is available.
T4 can either turn into an active T3 or into inactive reverse T3. There are people who make too much thyroid hormone (hyperthyroidism) or take too much thyroid hormone medicine. The body can reduce potential harmful effects of too much thyroid by turning it into reverse T3.
The important point here is that people who seemingly have normal T4 level may not have normal amount of the active T3. Let’s look at some of the factors that reduce T4 to T3:
1. Illness, acute or chronic. Especially kidney and liver disease, but any illness may reduce the conversion.
2. Stress, physical or phycological.
3. Not getting enough sleep.
4. Caloric restriction, dieting, fasting and starving.
5. Medications: betablockers, steroids (prednisone), high doses of iodine, amiodorone, anti-thyroid medications used in people with overactive thyroid, for example a drug called PTU.
6. Deficiency of certain minerals, especially zinc and selenium, but also iron, copper, magnesium, manganese and a few others.
7. Chronic inflammation. This could be a disease like rheumatoid arthritis, an allergy, chronic infection. Chronic inflammation has been linked to other diseases, including heart disease.
8. Heavy or toxic metals, like aluminum, cadmium, mercury. We are all exposed to those and whenever possible it is a good idea to encourage your detoxification system to get rid of them. I’ll speak about it in one of the future lectures.
9. Genetics. Like with everything else in the body, genetics plays a role in how your enzymes work and how well you turn T4 into T3.
10. Getting older. Things generally slow down with age, and this includes the de-iodinases, which slows down T4 to T3 conversion. That’s why it’s important to get enough thyroid supporting nutrients, like the minerals I mentioned, certain vitamins and some herbs that support thyroid regardless of your age.
Now let’s look at the factors that improve T4 to T3 conversion. That will be pretty much the opposite of what I said about reduced conversion.
1. Nutritional factors – adequate iodine, zinc, selenium, magnesium, iron, copper, vitamin A, vitamin D and pretty much all nutrients. Thyroid cells need the same nutrients as all the other cells, plus more Iodine and more tyrosine.
2. Stress management and relaxation. Relaxing minerals like Magnesium, herbs like Ashwagandha, Ginseng, Eleuthero and stress reducing techniques.
3. Adequate sleep.
4. Support healthy gut – we’ll have separate lectures on that
5. Reduce exposure to toxins. Thant includes avoiding processed foods that have strange sounding ingredients, like butylated hydroxytoluene (BHT).
6. Make sure you are not low in iodine and reduce goitrogens, the foods that interfere with iodine absorption. You can download a free special report from LowThyroidDoctor.com on how to check if you are low in iodine and I will mention it in the upcoming lecture.
7. If you are taking thyroid medications, make sure you get the right dose and the right kind. Plus, make sure you are taking them correctly and have your complete thyroid tests regularly. I will cover all that in the upcoming lectures.
In this lecture we talked about the fact that T4 can be converted to active T3 or to inactive revere T3. We also discussed factors that reduce T3 production and factors that improve it.
So far we have been discussing how thyroid should work when everything is normal. Staarting with the next lecture we’ll start talking about hypothyroidism or low thyroid. We will begin with the common symptoms.
If you know someone who might be interested in low thyroid, please refer them to LowThyroidDoctor.com so they can download this ebook. Also, if you have questions or comments, please email to DrTeplisky@gmail.com.
As an additional bonus, while available, you can get a free, no obligation 30 min phone consultation with me to see if I can help you figure out if you have low thyroid and what I can do to help you. Just book it online or call my office at 718-769-0997.